Operators of tractor-trailer trucks must monitor the weight carried at each axle of a tractor-trailer in order to comply with highway laws. A load must be distributed in the trailer so that the weight carried by each axle is within a legal limit. It is difficult to determine the weight supported by each axle of a tandem axle tractor-trailer.
Conventionally, weight carried by each axle of a tractor-trailer is determined by using a drive-up truck weigh station. Drive-up weigh stations measure the weight carried by a tractor-trailer axle at the tires. The tires of each axle are positioned on top of a scale to find the amount of weight carried by the axle.
Drive-up truck weigh stations are expensive. These stations are operated by truck stops or a governmental entity and are often located at remote sites. The loaded trailer must be driven to the weigh station for weight determination, consuming fuel and time. Further, considerable time is often spent waiting for the scale to be available if other trailers are being weighed as well. Fees are charged to use the weigh station.
Onboard scales for measuring the weight carried at each axle of air ride tractor-trailers are known. Load cells are installed between the axles and the air ride suspension. These systems are expensive to purchase, install and maintain and are complicated to use.
Thus, there is a need for an on board weight system for tractor-trailers and method for determining the weight at each axle of a loaded tractor-trailer without the necessity of traveling to a weight station. The system should be inexpensive, reliable, and easy to use.